Since the FDA launched its new veterinary feed directive (VFD) policies in January 2017, numerous producer questions have centered on the use of chlortetracycline (CTC) for control of anaplasmosis. In particular, producers have expressed confusion over free-choice versus hand-fed applications of feeds or supplements containing CTC.
In the past, some producers have used medicated feeds in “extra-label” applications, such as for prevention of anaplasmosis. By law, use of medicated feeds in cattle must comply with the product label. The new VFD rules ended over-the-counter (OTC) purchase of those feeds, with requirements for veterinarians to provide a VFD order in the context of a valid veterinarian-client-patient relationship. The veterinarian thus became more accountable in assuring that medicated feeds are used in accordance with the label.
To address those questions and provide more clarity, FDA has released a new document listing answers to the most frequently asked questions on the topic. The document provides assistance with the appropriate selection and use of approved VFD free-choice medicated feed for the control of active infection of anaplasmosis in cattle.
Anaplasmosis is an infectious disease of cattle, sheep, and goats. The disease, which can be acute or chronic, is transmitted in cattle by the organism Anaplasma marginale, a member of the Rickettsia family of disease-causing agents. Anaplasmosis is spread by bites from ticks, horseflies, and other biting insects, along with any instrument that can transmit blood such as syringes.
The FDA acknowledges that the ability to medicate animals through supplemental nutrition can be important to animal health, while noting that only approved free-choice medicated feed formulations may be used legally, to assure safety and effectiveness.
Currently, several oxytetracycline injectable drug products are approved for the treatment of anaplasmosis. FDA provides a summary of the approved use conditions for those products in 21 CFR 522.1660aand 522.1662a.
Also, several Type C medicated feeds containing CTC, including complete medicated feeds some free-choice medicated feed formulations, are approved for control of active infection of anaplasmosis. Find a list of those feeds and approved uses in 21 CFR 558.128.
FDA stresses though, that Type C medicated feeds containing CTC are only approved for the control of active infection of anaplasmosis. Currently, those feeds are not approved for the treatment or prevention of anaplasmosis.
FDA defines free-choice medicated feeds as products that contain one or more animal drugs and are placed in feeding or grazing areas for animals to freely consume. It is critical that the product’s composition and consumption rate of the feed are consistent with the approval, to provide safety and efficacy and prevent violative drug residues in human food. The FDA has posted two Blue Bird labels with the formulation for Type C Medicated Cattle Free-Choice Mineral Feed containing 6,000 grams per ton of CTC. This labeling is for an approved free-choice salt-mineral mix containing CTC, for use in beef and non-lactating dairy cattle as an aid in the control of active infection of anaplasmosis from one of two specific Type A medicated articles:
The FDA has also approved several proprietary formulations for the use of CTC in free-choice medicated feeds for control of anaplasmosis. Only the sponsors of proprietary formulations or the entities with access to them are able to manufacture such free-choice medicated feeds. Unlike publicly available formulations, which may be manufactured at any feed mill, proprietary formulations may only be manufactured at a licensed feed mill.
The FDA notes that once a veterinarian has determined an anaplasmosis infection exists within a herd, he or she may write a VFD to direct the use of CTC for controlling the progression of the disease in that herd, whether or not clinical signs are apparent yet.
As for ‘hand’fed” products, several combination medicated feeds containing CTC with lasalocid are approved for hand-fed feeding to cattle for control of active infection of anaplasmosis. FDA defines hand-fed as a feeding system in which a medicated feed is fed:
- To groups of animals.
- On a daily (24-hour period) basis.
- For the approved duration of feeding.
- In amounts that may (but do not necessarily) constitute the animals’ complete diet, which are intended to provide the entire approved daily drug dose over the course of the 24-hour period.
Read the full FAQ document from FDA.